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A105852 sigma(n) mod 9. 4
1, 3, 4, 7, 6, 3, 8, 6, 4, 0, 3, 1, 5, 6, 6, 4, 0, 3, 2, 6, 5, 0, 6, 6, 4, 6, 4, 2, 3, 0, 5, 0, 3, 0, 3, 1, 2, 6, 2, 0, 6, 6, 8, 3, 6, 0, 3, 7, 3, 3, 0, 8, 0, 3, 0, 3, 8, 0, 6, 6, 8, 6, 5, 1, 3, 0, 5, 0, 6, 0, 0, 6, 2, 6, 7, 5, 6, 6, 8, 6, 4, 0, 3, 8, 0, 6, 3, 0, 0, 0, 4, 6, 2, 0, 3, 0, 8, 0, 3, 1, 3, 0, 5, 3, 3 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

COMMENTS

If gcd(m,n) = 1 then a(m*n) = (a(m) * a(n)) mod 9. - Robert Israel, Sep 14 2014

LINKS

Robert Israel, Table of n, a(n) for n = 1..10000

FORMULA

a(n) = A010878(A000203(n)). - Michel Marcus, Sep 14 2014

MAPLE

seq(numtheory:-sigma(n) mod 9, n=1..1000); # Robert Israel, Sep 14 2014

PROG

(PARI) a(n)=sigma(n)%9

CROSSREFS

Cf. A190998 (digital root of sigma(n)).

Sequence in context: A323394 A017665 A248789 * A190998 A067342 A322656

Adjacent sequences:  A105849 A105850 A105851 * A105853 A105854 A105855

KEYWORD

easy,nonn

AUTHOR

Shyam Sunder Gupta, May 05 2005

EXTENSIONS

Name corrected and keyword base removed by Michel Marcus, Sep 14 2014

STATUS

approved

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Last modified April 20 16:17 EDT 2019. Contains 322310 sequences. (Running on oeis4.)